I'm planning on getting an Alienware X51 but i'm a bit skeptical about it. There's several graphics card choices.

NVIDIA Graphics Cards:

NVIDIA GeForce GTX 745 with 4GB DDR3
NVIDIA GeForce GTX 750Ti 2GB GDDR5
NVIDIA GeForce GTX 760 Ti with 2GB GDDR5

AMD Radeon Graphics Cards:
AMD Radeon R9 270 with 2GB GDDR5

And there are some processor choices:

4th Generation Intel Core i3 Processor
4th Generation Intel Core i5 Processor
4th Generation Intel Core i7 Processor

My current computer sucks and I'm in need of some recommendations on my computer choices.

It doesn't matter which of these options you choose, this game is from 2008!
Every new Alienware will be capable of running it at highest settings.

I have that amd card and its great no issues but yea theres no issues with any alienware pc

The cheapest option for this computer is $649 and it has this processor: 4th Generation Intel Core i3-4150 Processor

That's not a very good cpu

The Intel Core i3-4150 Processor will work fine to run this game. What you need to take into consideration is what else will you be doing while playing CZ? For instance, take into consideration if you plan to use any sort of video recording software for game capture or live streaming programs, voice/video chat programs such as skype. If you are into creating maps and such you could very well find yourself running multiple programs as well while working on your project.  Running all these programs concurrently will use a high percentage of the I3 and you might have some noticeable problems.

 If its not a major difference in price I would suggest to opt for the I5 quad core. Make sure you take notice which I5 you are looking at because they are not all quad core.

Hope this might have helped shed some light.

even the I3 is miles over the requirements for running WaW

Even with recording

But like previously said, if your a heavy user, that uses multiple things at once (like me) then I would suggest the i5 or 7